McDonnell XHJH Whirlaway
|Role||Experimental twin-rotor helicopter|
|National origin||United States|
|First flight||27 April 1946|
The McDonnell XHJH Whirlaway was a 1940s American experimental twin-rotor helicopter designed and built by McDonnell Aircraft for the United States Navy. It was the first successful twin-engined, twin rotor helicopter in the world. The Whirlaway was the largest helicopter flown up to that time.
Design and development
In 1944, the United States Navy issued a requirement for a large rescue helicopter with capacity for ten occupants. The design was originally designated XHJD-1; shortly after flying it was re-designated the XHJH-1. The XHJH-1 first flew in August 1944, and had twin side-by-side 46 ft (14 m) rotors at the end of pylon wings which turned in opposite directions. Each rotor was powered by a 450 hp (336 kW) Pratt & Whitney R-985 engine.
- Original United States Navy designation.
- Designation changed before first flight.
Aircraft on display
Data from 
- Length: 32 ft 2 in (9.80 m)
- Powerplant: 2 × Pratt & Whitney R-985 , 450 hp (340 kW) each
- Main rotor diameter: 2× 46 ft 0 in (14.02 m)
- Maximum speed: 120 mph (190 km/h, 100 kn)
- Cruise speed: 90 mph (140 km/h, 78 kn)
- Range: 300 mi (480 km, 260 nmi)
- Andrade 1979, p. 194
- "American airplanes - McDonnell". www.aerofiles.com. 25 March 2008. Retrieved 2010-02-16.
- "The War Years: 1939-1945". Boeing. Archived from the original on 2007-07-07. Retrieved 2007-07-07.
- "McDonnell XHJD-1 Whirlaway". National Air and Space Museum. Smithsonian Institution. Retrieved 12 August 2019.